Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Reexamination Certificate
1999-02-12
2001-04-17
Schwartz, Christopher P. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
Reexamination Certificate
active
06217128
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to steering assist systems. More particularly, the present invention relates to hydraulic valving arrangements for steering assist systems or other systems where precise equal braking pressures are desirable.
BACKGROUND OF THE INVENTION
Steering assist vehicles are advantageous because they are highly maneuverable. A typical steering assist vehicle is turned by driving the wheels on one side of the vehicle at a different speed than the wheels on the other side of the vehicle. Also, turning can be achieved by stopping the wheels on one side of the vehicle, while driving the wheels on the other side of the vehicle. When braking a steering assist vehicle, it is desirable to have equal braking pressures on both sides of the vehicle to prevent unintentional turning. Examples of typical steering assist vehicles include farm tractors, construction backhoe loaders, farm combines, as well as other vehicles.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a valve arrangement for use with a steering assist system having left and right actuating members. The valve arrangement includes a valve body defining a left brake port adapted for connection to a left hydraulic brake and a right brake port adapted for connection to a right hydraulic brake. The arrangement also includes a left brake valve member for controlling hydraulic fluid flow through the left brake port, and a right brake valve member for controlling hydraulic fluid flow through the right brake port. The left and right brake valve members are adapted to the actuated, respectively, by left and right brake actuating members. The valve arrangement also includes means for providing the highest pressure present at either of the first and second brake valve members to both the first and second brake ports, wherein equal braking pressures are provided to the first and second brakes even when the first and second brake actuating members have been actuated unequal amounts.
Another aspect of the present invention relates to a steering assist system including left and right hydraulic brakes, and left and right actuating members for respectively actuating the left and right brakes. The system also includes a valve body defining a left brake port connected to the left hydraulic brake and a right brake port connected to the right hydraulic brake. The valve body also defines left and right brake pressure ports connected to a source of hydraulic pressure. The valve body further defines a left brake passageway for providing fluid communication between the left brake pressure port and the left brake port, and a right brake passageway for providing fluid communication between the right brake pressure port and the right brake port. The steering system further includes a left brake valve member for controlling hydraulic fluid flow through the left brake port and through the left brake pressure port, and a right brake valve member for controlling hydraulic fluid flow through the right brake port and through the right brake pressure port. The left and right brake valve members are respectively operatively coupled to corresponding left and right brake actuating members. A bypass passage arrangement provides fluid communication between the left brake passageway and the right brake port, and also provides fluid communication between the right brake passageway and the left brake port. A plurality of valves function to: (1) close the left brake passageway and direct hydraulic fluid from the right brake passageway through the bypass passage arrangement to the left brake port when the right brake actuating member has been actuated more than the left brake actuating member; and (2) close the right brake passageway and direct hydraulic fluid from the left brake passageway through the bypass passage arrangement to the right brake port when the left brake actuating member has been actuated more than the right brake actuating member.
A variety of advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
REFERENCES:
patent: 3945685 (1976-03-01), Page et al.
patent: 3945691 (1976-03-01), Page et al.
patent: 4010983 (1977-03-01), Coupland
patent: 4030560 (1977-06-01), Parquet et al.
patent: 4074782 (1978-02-01), Bauer
patent: 4139238 (1979-02-01), Hoffman
patent: 4260197 (1981-04-01), Hawker
patent: 4380249 (1983-04-01), Behlmer et al.
patent: 4399896 (1983-08-01), Bahlmer
patent: 4498710 (1985-02-01), Smith
patent: 4553789 (1985-11-01), Pugh et al.
patent: 4609230 (1986-09-01), McCann
patent: 4629256 (1986-12-01), Fannin
patent: 4691968 (1987-09-01), Pugh et al.
patent: 4880282 (1989-11-01), Makino et al.
patent: 4949805 (1990-08-01), Mather et al.
patent: 4962825 (1990-10-01), Albright et al.
patent: 5161862 (1992-11-01), Kunz
patent: 5354123 (1994-10-01), Albert
patent: 5380073 (1995-01-01), Bartscher et al.
patent: 5407033 (1995-04-01), Weiler et al.
patent: 5456523 (1995-10-01), Boehringer
patent: 5531512 (1996-07-01), Thompson
patent: 5735314 (1998-04-01), Alaze et al.
patent: 5778672 (1998-07-01), Durant et al.
patent: 5802853 (1998-09-01), Oberst et al.
patent: 0 272 032 (1988-06-01), None
Bartz C. T.
Merchant & Gould P.C.
Mico, Inc.
Schwartz Christopher P.
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